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No. 6l6,7l5. Patented Dec. 27, I898.

J. LYALL.

STEAM GENERATOR.

(Application filed Dan. 27. 1897.) Modem 2 Sheets-Sheet l.

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NITE STATES JOHN LYALL, OF. GLASGOXV, SCOTLAND.

STEAM-G EN ERATO R.

SPECIFICATION forming part of Letters Patent No. 616,715, dated December27, 1898.

- Application filed December 27, 1897. $erial No. 663,620. (No model.)

Improvements in Steam-Generators, (which have been patented in GreatBritain by Letters Patent dated July 8, 1892, No. 12,609,) of which thefollowing is a specification.

This invention relates to steam-generators, and has for its object toprovide awater-tube and fire-tube generator of improved construction.

In the accompanying drawings, which illustrate the invention, Figure 1is a longitudinal vertical section of a modification of the improvedsteam-generator as adapted for marine purposes. Fig. 2 is partlyan endelevation and partly an end section, and Fig. 3 a horizontal section,partly through the Watertubes and partly through the fire-tubes, of thesame. Fig. 4 is a longitudinal vertical section of a double-ended marineboiler with a water-space dividing the combustion-chamher.

The improved steam-generator is composed of a double shell A A, theinterior one, A, of which constitutes the furnace or fire-box and haswithin it a series of tubes 13, extending from front to back andcommunicating at both ends with the Water-space of the generator.

The upper portion or fire-tube section of the generator is composed ofan ordinary boilerdrum D, with open-ended fire-tubes F extendingthroughout its length, or from the combustion-chamber end to the uptakeend. The boiler-drum is connected to the water-tube section belowthrough water-legs formed by the double shell A A.

The interior shell A, forming the furnace or fire-box, is inclosed byclose-fitting outside rows of Water-tubes extending upward from thefire-bars to the cylindrical shell, as indicated at Figs. 1, 2, and 3. Aplate-casing is fittedv outside this outer row of tubes, and between thetubes and casing is packed non- At the rearward end the interiorshell'or fire-box A is extended upward to constitute acombustion-chamber 0, like the fire-box of a locomotive-boiler, or, asshown in Fig. 4, the combustion-chamber may be formed outside of theboiler proper and composed of a casing O, lined with firebrick. Theupper chamber of the interior shell is fitted with fire-tubes F,extending from the fire-box to the end of the boiler, and

has a manway at the bottom of the combustion-chamber to afiordaccess tothe furnace or fire-box and to afford facility for repairing, cleaning,or renewing the fire-tubes extending through the interior shell. Thefront and back ends of the exterior shell have a door or doors Hopposite the ends of the water-tubes for fitting, unfitting, or cleaningthe tubes, the said holes being closed by plugs or caps of suitableconstruction screwed in or held in position by bridges and screws andrendered steam and water tight, coming metal to metal, or byindia-rubber, asbestos, or other packing. The side walls of the furnaceor lower part of the marine boiler are composed of water-tubes 13,connected to the water-legs, as shown at Figs. 2 and 3, the tubes beingtapered at their ends, which are expanded into the inner shell A. Fromthe fire-grate the gaseous products of combustion pass upward betweenthe tubes B and through the flueport E into the combustion-chamber O,and thence through the fire-tubes F into the smokebox or uptake G of thegenerator.

The modification shown at Fig. 4 is a doubleended marine boiler with awater-space dividing the combustion-chamber, but it may be formedwithout the water-space, the combustion-chamber being in the latter casecommon to both ends of the boiler.

Having now described the invention, what I claim, and desire to secureby Letters Patent, is-

A steam-generator composed of a double shell the interiorof whichconstitutes the furnace or fire-box and is fitted with a series ofwater-tubes communicating with a waterspace at both ends, a boiler-drumwith openended fire tubes extending throughout its length, connected bywater-legs to the watertube section or shell below, and acombustionchamber formed within the space at the rear of the fire-tubesand connected bya flue port or ports with the furnace-chamber,substantially as described.

Signed at Glasgow, Scotland, this 10th day of-December, 1897.

' JOHN LYALL. \Vitnesses:

WALLACE FAIRWEATHER, JNo. ARMSTRONG, J unr.

